This means avoiding gossip, lies, empty promises and other ways we cause problems with our words. Say only what you mean, and realize that you can cause damage if you’re not careful with what you say.

This is a great recommendation. Many people don’t realize the power of their words and see the harm that can be caused with speaking carelessly, thoughtlessly or aggressively. Most of us are aware that screaming at someone may be upsetting to them, but subtle little digs at them, or gossip behind their backs, can hurt others more than we realize, and in hurting them, we hurt ourselves. This is an important, but difficult one to follow entirely. It’s a great goal to aspire to, though, and a good direction to work toward.

The Second Agreement: Don’t Take Anything Personally

This ‘agreement’ deals with understanding how other people’s behaviors are a reflection of them only. When someone gives us feedback about us, it’s important to remember that no opinions are truly objective; we all have our biases, ‘filters’ through which we view the world, and the like. Because of this, we shouldn’t take anyone else’s view of us or our actions as entirely accurate; when someone says something about us (or anything else), they’re really saying something about themselves and how they view the world.

This is good advice for making us feel better, but take it with a grain of salt. While everyone has their biases and there is no such thing as true objectivity, by never taking anything personally, people can really limit their ability to see their own negative patterns and biased thinking, and work on developing more healthy patterns and clear-sighted thinking. As M. Scott Peck says in The Road Less Traveled, “the problem of distinguishing what we are and what we are not responsible for in this life is one of the greatest problems of human existence.” Don’t give up on the work of distinguishing responsibility, or you end up creating more stress in the long run.

The Third Agreement: Don’t Make Assumptions

Much stress is created when people assume they know what other people are thinking without checking with them. Understanding that other people might have different motivations for their actions, even drastically varying world views, and remembering to really try to understand others and discuss these motivations before jumping to conclusions about their behavior, can go a long way toward preventing interpersonal conflict.

However, taking this advice to an extreme may cause people to ignore their intuition about people, or common sense about someone’s behavior that’s damaging. It can also open people up to manipulation if they train themselves to believe someone’s explanation of negative behavior rather than judging the behavior on its own. (For example, not ‘assuming’ they’re being cheated on if their spouse is exhibiting erratic behavior and the classic signs of infidelity, but vehemently denies wrongdoing.) This one is a good suggestion, but should be tempered by inner wisdom and common sense.

The Fourth Agreement: Always Do Your Best

By this, Ruiz means to do the best you can at any given moment, and you’ll have no regrets. Some days, your best isn’t as good as other days, and that’s okay. As long as you put an honest effort into life, you will have nothing to be ashamed of, and will not ‘beat yourself up’ over a less-than-stellar performance in retrospect.
I think this is good advice for anyone, and see no down-side to it. This behavior can help people acheive more progress toward their goals, and prevent unecessary feelings of regret.

While sometimes the ‘agreements’ are oversimplified, in my opinion, this is still a great little book with some heavy ideas. If followed generally (and not fanatically), these suggestions can help you reduce a great amount of stress by helping people avoid thought and behavior patterns that create frustration, blame, hurt feelings and other negative emotions.